Furnace wall cooling

ABSTRACT

Blast furnace walls are cooled by circulation of water through cooling plates provided with baffles to control cooling water flow. The baffles include a J-shaped baffle, a central baffle, and two stub baffles. Streamlined protrusions on the baffles, the stub baffles themselves, and a flared water passage minimize whirlpool action within the plate, thereby avoiding low water throughput, sedimentation and resultant overheating which leads to failure of the cooling plate. An aperture in the central baffle vents air to a water discharge outlet, to prevent entrapment of air within the plate and concomitant production of water-void areas which also promote plate overheating.

United States Patent Edward ,I. Ostrowski Steuhenville, Ohio [2|] Appl. No. 840,272

[22] Filed July 9,1969

[45} Patented Aug. 10, 1971 [7 3| Assignee National Steel Corp.

[72] Inventor [S4] FURNACE WALL COOLING 3,325,l59 6ll967 Loecher....,....

ABSTRACT: Blast furnace walls are cooled by circulation of water through cooling plates provided with baffles to control cooling water flow. The baffles include a .l-shaped bafile, a central baffle, and two stub baffles. Streamlined protrusions on the baffles, the stub baffles themselves, and a flared water passage minimize whirlpool action within the plate, thereby avoiding low water throughput, sedimentation and resultant overheating which leads to failure of the cooling plate. An aperture in the central baffle vents air to a water discharge outlet, to prevent entrapment of air within the plate and concomitant production of water-void areas which also promote plate overheating.

PATENTED AUG] 0 I971 FIG. 4

INVENTOR EDWARD J. OSTROWSK! FIG. I

ATTORN EYS FURNACE wxu. coounc BACKGROUND OF THE INVENTION.

This invention pertains to metallurgical apparatus, and more particularly, to shaft furnace cooling equipment.

Metallurgical shaft furnaces are often subjected to such high-temperature conditions that coolingsystems must be provided for the furnace walls. Water-cooled plates are customarily installed in the bosh'and stack of an iron blast furnace to cool the refractory lining and other parts of the furnace walls; I

Circulation of water through a cooling plate must be in a manner which provides effective cooling of the furnace wall and long service life for the cooling plate. The cooling plate must have an extended service life, because costly operating delays are incurred on a furnace whenever a cooling plate burns through and must be replaced; In large blast furnaces currently 'employed'inthe steel industry, the service 'life of conventional cooling plates is unsatisfactorily short,v and operating delays resulting from plate failure are aproblem. Hence, a need exists for a cooling plate having a longer service life, and a main object of the invention is the fulfillment of this need.

It has been discovered that conventional cooling plates have a number of deficiencies which retard extractionof heat from the furnace walls by the cooling'water flow, and thus promote overheating and resultant early failure of the cooling plate. Among these deficiencies is the existence within the cooling plate of large areas of whirlpool action where much cooling water remains for extended periods, bypassed by the main flow of coolant. This promotes overheating of the cooling plate at the regions of the Whirlpools. Heat exchange at the whirlpool regions is further retarded by sediment, which tends to be eposited by the coolant and accumulate at these regions. ediment accumulation also promotes overheating at the locality of the Whirlpools.

Another deficiency found in conventional cooling plates is the presence of large water-void areas within the plate. Such voids result from entrapment of air in the plate, and'the'watervoid regions, like the regions of the whirlpools, tendtooverheat and lead to failure.

A Accordingly, further objects of the invention are the provision of improved cooling plates in which whirlpool action, sedimentation, and air entrapment are minimized.

Other objects and advantages of the invention will appear from the following detailed description which, considered with the accompanying drawings, discloses a preferred embodiment of the invention for purposes of illustration only. For definition of the scope of the invention, reference will be made to the appended claims.

. BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT FIGL I depicts a portion of a blast furnace bosh wall I including a refractory lining I2 surrounded by a shell 14 of steel plates. Shell 14 carries a plurality of plate holders 16, which can be of any suitable type of conventional design. Each holder 16 is operatively connected to support a cooling plate 18 which is passed through an aperture in the shell and embedded in monolithic refractory forming part of furnace lining l2. The plates are vertically spaced apart, and provided around the furnace periphery. Each cooling plate is in heat exchange relationship with refractory lining 12 by virtue of being embedded therein, and is provided with water-coolant supply and discharge conduits 20, 22 respectively (FIG. 2). Water circulates through the plate to coolthe lining and portions of the shell contiguous to the plate. a

Each cooling plate includes a hollow body 24 of material of high thermal conductivity, e.g., copper. The body includes a backwall 26, a front or nose wall 28 opposite and generally parallel to backwall 26, and opposing side walls 30, 32 which join the back and front walls. Sidewalls 30, 32 converge in a direction toward front wall 28, so plate 18 tapers toward its nose end in the plane of walls 26, 28, 30 and 32. Plate 18 includes a convex top wall 34 (FIG. 3) and a flat bottom wall 36, with top wall 34 convergent on bottom wall 36 in a direction toward front wall 28 (FIG. 4). The walls of plate 18 define a cavity 38 (FIG.'2) in which the cooling water circulates.

A plurality of baffies within cooling plate 18 divide coolant cavity 38 into a plurality of waterflow passages, and control theflow of water. A generally J-shaped directional baffle 40 includes afirst section 42 extending from juncture with backwall 26 along sidewall 30 towards front wall 28, a second section 44 extending along front wall 28 towards sidewall 32, and a third section 46 extending along sidewall 32 toward backwall 26. Baffle section 46 includes an end 48 at which baffle 40 tenninates. End 48 is spaced from back wall 26 to permit flow of water around the end of baffle 40. Baffle sections 42, 44, 46 are spaced respectively from the plate walls along which the baffle sections extend, and the baffle sections curve smoothly into one another to define within cavity 38 a continuous, generally J-shapcd water passage 50. Baffle sections 42, 44 are generally parallel to plate walls 30, 28 respcc tively. However, section 46-gradually inclines away or recedes from sidewall 32 in a direction toward the longitudinal centerline of the plate, so that water passage 50 has a flared discharge end portion which aids materially in reducing whirlpool action in the region of the end of baffie 40.

A second directional baffle 52 is disposed along the longitudinal centerline of plate 18, and extends transversely from juncture with backwall 26 toward baffle section 44. Bafile 52 has an inner end portion 54 spaced from baffle section 44, to permit water flow around the inner end of baffle 52. The construction and arrangement of baffle 52 provides a generally U- shaped water passage 56 in the rear central portion of plate I8.

Baffle 52 includes a streamlined protrusion 58 at inner end portion 54, to retard whirlpool action in the region of the inner end portion of baffie 52 by streamlining water flow in that region. Streamlined protrusion 58 includes a generally cylindrical surface 60 extending from bottom wall 36 to top wall 34' of plate l8. Streamlined surface 60 projects from baffle 52 in a direction toward section 46 of baffle 40, curves around the inner end of baffle 52 and joins with a side surface 62 of baffle 52 which faces away from baffle section 46. Surface 62 is flat and free of protrusions from the inner end of baffle 52 to the location of a fillet 63 which marks the juncture of baffle 52 with backwall 26. This construction of surface 62 prevents development of a relatively static region of water along baffle 52 between baffle 52 and baffle section 42.

In generally the central portion of plate 18, closely adjacent inner end portion 54 of baffle 52, are located third and fourth baffles 64, 66. Baffles 64, 66 are spaced from both baffie 52 and baffle 40, for flow of water in the spaces among thebaffies. Raffles 64, 66 are respectively located on opposite sides of inner end portion 54 of baffle 52, and incline away. from baffle 52 and from each other in directions toward plate front wall 28.

Baffles 64, 66 respectively include streamlined protrusions 68, 70 which project in directions toward baffle section 46. Like streamlined protrusion 58 of heme 52, each of the streamlined protrusions 68, 70 includes a generally cylindrical surface extending from the bottom wall to the top wall of plate 18 to streamline water flow in the region of the protrusion. Each streamlined surface extends over about half the length of the respective baffles 64, 66,.and the remainder of the side of the baffle which faces baffle section 46 is flat. Since baffles 64, 66 radiate outwardly from baffle 52, one end portion of each of baffles 64, 66 is closer to baffle 52 than the opposite end portion, and protrusions 68, 70 are respectively located at the end portions of baffles 64, 66 which are more remote from baffle 52. Baffles 64, 66 respectively, include side surfaces 72,

74 which face away from baffle section 46, and are flat and free of protrusions. The ends of baffles 64, 66 which are more remote from baffle 52 are spaced from baffle section 44 a distance slightly less than the distance of the inner end of baffle 52 from section 44.

Each of baffles 64, 66 is very shortas compared to baffle S2 or 40, and breaks up any whirlpool which tends to form at its location. Thus, streamlined protrusion 58 on baffle 52, and stub baffles 64, 66 coact to combat whirlpooling turbulence in U-shaped water passages 56 at the region of the inner end of baffle 52 where the water flow reverses in direction.

Baffie 52 includes a vent aperture or slot 76, which is formed in baffle 52 at a location adjacent top wall 34 and backwall 26. Vent aperture 76 prevents entrapment of air against backwall 26 between baffle 52 and sidewall 32 by allowing the air to escape through baffle 52 to the region adjacent coolant discharge conduit 22 so that the air can pass out with exiting water through the discharge conduit.

In use, water enters plate 18 through a coolant inlet passageway 78 which is formed in backwall 26 at a location between sidewall 30 and baffle section 42 and is in communication with coolant supply conduit 20. Entering water passes through J-shaped water passage 50 directly to the nose end portion of plate 18, so that cooling water at its lowest temperature is-applied at the portion of the plate where the highest temperature prevails. After passing through J-shaped passage 50 and outwardly 'through the flared discharge portion thereof, the water enters and passes through U-shaped passage 56, completely reversing its direction by virtue of the inner end of baffle 52 being spaced from backwall 26 a distance greater than the distance from backwall 26 of end 48 of baffle 40.

After reversing direction, the water flows around streamlined protrusion 58 and baffles 64, 66. again reversing flow direction while cooling the central portion of the plate. The water emerges from plate 18 through a coolant outlet passageway 80 formed in backwall 26 at a location between bafile 52 and baffle section 42. Water is discharged through coolant discharge conduit 22, which communicates with coolant outlet passageway 80. The walls of coolant passageways 78, 80 are threaded for connection to the respective conduits.

Furnace cooling plates according to the invention are highly advantageous in minimizing whirlpool action and resultant ineffective cooling caused by high residence time of water and sedimentation in the whirlpool regions, which contribute to plate overheating and failure at the regions of the whirlpools. Air is vented to discharge rather than remaining within the cooling cavity, so that water-void areas which are caused by entrapped air and which are also subject to overheating, are avoided. To further streamline water flow, oversize fillets 82, 63, 84 and 86 are employed at the juncture of backwall 26 with baffle section 42, baffle 52, and sidewall 32, respectively. For a plate 2 feet 4 inches long and 2 feet wide at the backwall, fillets of at least about 3-inch radius are satisfactory.

As indicated above, accumulation of sediment deposited in the cooling plate by the water impairs heat exchange between the furnace wall and the cooling water. Sedimentation result ing from whirlpooling is effectively controlled in accordance with the invention. However. it has been found that sedimentation can occur at various regions throughout the cooling plate if the water velocity is inadequate to maintain entrained solids in suspension over the entire path of travel of the water through the plate. The higher the flow rate, the less the sedimentation, but since the velocity of the water decreases as it traverses its tortuous path through the plate, water may enter the plate at sufficient velocity to avoid deposition of sediment near the inlet, but solids may settle out in the central sections of the plate where the water velocity has decreased below the minimum velocity necessary to suspend the entrained solids. It has been found that no settling of solids occurs anywhere in the plate when the water enters the plate at velocities of about 36.7 feet per second and above.

Although the invention has been described in connection with a preferred embodiment, modifications thereof can be made without departing from the principles of the invention. Such modifications are within the scope of the appended claims.

lclaim: I

1. A shaft furnace, comprising 1 a wall having a refractory lining, and

a plurality of cooling plates in heat exchange relationship with the refractory lining,

each cooling plate including a thermally conductive hollow body at least partially embedded in the refractory lining,

the hollow body including a backwall, a front wall opposite the backwall, and opposing first and second sidewalls joining the back and front walls,

a first baffle including a first section spaced from the first sidewall and extending from the back wall along the first sidewall towards the front wall, a second section spaced from the front wall and extending along the front wall toward the second sidewall, and a third section spaced from the second sidewall and extending along the second sidewall toward the backwall,

the third section having an end spaced a distance from th backwall,

the first baffle terminating at the end of the third section;

a second baffle disposed transversely to the second section of the first baffle and extending from the backwall toward the second section of the first baffle and having an inner end portion spaced a distance from the second section of the first bafile,

the second baffle including a streamlined protrusion at the inner end portion,

means defining a first coolant passageway in the backwall at a location between the first sidewall and the first section of the first baffle, and

means defining a second coolant passageway in the backwall at a location between the second baffle and the first section of the first baffle.

2. The shaft furnace of claim I,

at least a terminal portion of the third section of the baffle inclining away from the second sidewall in a direction toward the second baffle.

3. The shaft furnace of claim 1, including coolant supply means communicating with the first coolant passageway, and

coolant discharge means communicating with the second coolant passageway.

4. The shaft furnace of claim 3,

the second baffle including a vent aperture located adjacent the backwall.

5. The shaft furnace of claim 4,

the body including a top wall, and

the vent aperture being located adjacent the top wall.

6. The shaft furnace of claim I,

the inner end portion of the second baffle being spaced from the buckwall a distance greater than the distance from the buckwall of the end of the third section of the first baffic.

7. The shaft furnace ofclaim l,

the streamlined protrusion projecting from the second bafge in a direction toward the third section of the first baf- 8. The shaft furnace of claim 7 third section of the first baffle and extending to juncture of the second battle with the backwall, and

the side surface of the second baffle being free of protru- SlOllS.

9. The shaft furnace of claim 8,

the body including a top wall and a bottom wall, and

the streamlined protrusion including a streamlined surface extending from the bottom wall to the top wall and joining the side surface of the second baffle.

10. A furnace-cooling plate, comprising a hollow body including a backwall, a front wall opposite the backwall, and opposing first and second sidewalls joining the back and front walls,

a first baffle including a first section spaced from the first sidewall and extending from the backwall along the first sidewall towards the front wall, a second section spaced from the front wall and'extcnding along the front wall toward the second sidewall, and a third section spaced from the second side wall and extending along the second sidewall toward the backwall,

the third section having an end spaced a distance from the backwall,

the first baffle terminating at the end of the third section,

a second baffle disposed transversely to the second section of the first baffle and extending from the backwall toward the second section of the first baffle and having an inner end portion spaced a distance from the second section of the first baffle,

the second baffle including a streamlined protrusion at the inner end portion,

a stub third baffle located on one side of the inner end portion of the second baffle.

a stub fourth baffle located on a side of the inner end portion of the second baffle opposite the third baffle.

each of the third and fourth baffles being spaced from the second battle and the first hafflc.

means defining a first coolant passageway in the backwall at a location between the first sidewall and the first section of the first baffle, and 1 means defining a second coolant passageway in the backwsll at a location between the second baffic and the first section of the first baffle.

11. The furnace-cooling plate of claim 10,

each of the third and fourth baffles inclining in a direction away from the second baffle and toward the front wall.

12. The furnace-cooling plate of claim 10.

the streamlined protrusion projecting from the second batfle in a direction toward the third section of the first bat" fie. and

each of the third and fourth baffles including a streamlined protrusion projecting in a direction toward the third section of the first baffie.

13. The furnace-cooling plate of claim 12,

- each of the third and fourth baffles including a first end portion adjacent the second baffle and a second end portion remote from the second baffle, and

the streamlined protrusions of the third and fourth baffles being located at the second end portions of the baffles.

14. The furnace-cooling plate of claim 12,

each of the third and fourth baffles including a side surface facing away from the third section of the first baffle, and

the side surfaces of the third and fourth baffles being free of protrusions.

15. The furnace-cooling plate of claim 12,

the body including a top wall and a bottom wall, and

each of the streamlined protrusions including a generally cylindrical surface extending from the bottom wall to the top wall.

16. The furnace-cooling plate of claim 10,

each of the third'and fourth baffles being spaced from the second section of the first baffle a distance less than the distance of the inner end portion of the second battle from the second section of the first baffle. 17. The furnace-cooling plate of claim 10,

the second bai'fle having a side surface facing away from the third section of the first bafflc and extending to juncture of the second baffle with the backwall. and

the side surface of the second baffie being free of protruareas.

18. The furnace-cooling plate of claim 17, Y

the body including atop wall and a bottom wall. and

the streamlined protrusion projecting in a direction toward the third section of the first baffle and including a streamlined surface extending from the bottom wall to the top wall and joining the side surface ofthe second battle.

I). The furnace-cooling plate of claim it),

at least a terminal portion of the third section of the first baffle inclining away from the second sidewall in a direction toward the second baffle.

20. The furnace=cooling plate of claim it). including coolant supply means communicating with the first coolant passageway. and

coolant discharge means communicating with the second coolant passageway.

21. The furnacc cooling plate of claim 20,

the second batflc including a vent aperture located adjacent the backwail.

22. The furnacecooling plate of claim 21,

the body including a top wall, and

the vent aperture being located adjacent the top wall.

m g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent Nm 3,598,382 Dated August 1.0, 1971 Inventor) Edward J. Ostrowski I: is certified that error appears in the above-identified patent and that: said Letter: Patent are hereby corrected as shown below:

column T 2, line 21, "waterflow'! should be water-flow Column 4, line 5' 1,' "the baffle" Should be the firt baffle Signed and sael edtthi's 21 s t :day of Ma-rqch 1972:. I T

. (SEAL) Attest: 7 EDWARD M.FLET :HE B. e ,RQBERT GOTTSCHALK Attesting Qffic'er T Y .Commisjsionen. qf. Ratente ur I I 1 n L- I I I I x 

1. A shaft furnace, comprising a wall having a refractory lining, and a plurality of cooling plates in heat exchange relationship with the refractory lining, each cooling plate including a thermally conductive hollow body at least partially embedded in the refractory lining, the hollow body including a backwall, a front wall opposite the backwall, and opposing first and second sidewalls joining the back and front walls, a first baffle including a first section spaced from the first sidewall and extending from the back wall along the first sidewall towards the front wall, a second section spaced from the front wall and extending along the front wall toward the second sidewall, and a third section spaced from the second sidewall and extending along the second sidewall toward the backwall, the third section having an end spaced a distance from the backwall, the first baffle terminating at the end of the third section; a second baffle disposed transversely to the second section of the first baffle and extending from the backwall toward the second section of the first baffle and having an inner end portion spaced a distance from the second section of the first baffle, the second baffle including a streamlined protrusion at the inner end portion, means defining a first coolant passageway in the backwall at a location between the first sidewall and the first section of the first baffle, and means defining a second coolant passageway in the backwall at a location between the second baffle and the first section of the first baffle.
 2. The shaft furnace of claim 1, at least a terminal portion of the third section of the baffle inclining away from the second sidewall in a direction toward the second baffle.
 3. The shaft furnace of claim 1, including coolant supply means communicaTing with the first coolant passageway, and coolant discharge means communicating with the second coolant passageway.
 4. The shaft furnace of claim 3, the second baffle including a vent aperture located adjacent the backwall.
 5. The shaft furnace of claim 4, the body including a top wall, and the vent aperture being located adjacent the top wall.
 6. The shaft furnace of claim 1, the inner end portion of the second baffle being spaced from the backwall a distance greater than the distance from the backwall of the end of the third section of the first baffle.
 7. The shaft furnace of claim 1, the streamlined protrusion projecting from the second baffle in a direction toward the third section of the first baffle.
 8. The shaft furnace of claim 7, the second baffle having a side surface facing away from the third section of the first baffle and extending to juncture of the second baffle with the backwall, and the side surface of the second baffle being free of protrusions.
 9. The shaft furnace of claim 8, the body including a top wall and a bottom wall, and the streamlined protrusion including a streamlined surface extending from the bottom wall to the top wall and joining the side surface of the second baffle.
 10. A furnace-cooling plate, comprising a hollow body including a backwall, a front wall opposite the backwall, and opposing first and second sidewalls joining the back and front walls, a first baffle including a first section spaced from the first sidewall and extending from the backwall along the first sidewall towards the front wall, a second section spaced from the front wall and extending along the front wall toward the second sidewall, and a third section spaced from the second side wall and extending along the second sidewall toward the backwall, the third section having an end spaced a distance from the backwall, the first baffle terminating at the end of the third section, a second baffle disposed transversely to the second section of the first baffle and extending from the backwall toward the second section of the first baffle and having an inner end portion spaced a distance from the second section of the first baffle, the second baffle including a streamlined protrusion at the inner end portion, a stub third baffle located on one side of the inner end portion of the second baffle, a stub fourth baffle located on a side of the inner end portion of the second baffle opposite the third baffle, each of the third and fourth baffles being spaced from the second baffle and the first baffle, means defining a first coolant passageway in the backwall at a location between the first sidewall and the first section of the first baffle, and means defining a second coolant passageway in the backwall at a location between the second baffle and the first section of the first baffle.
 11. The furnace-cooling plate of claim 10, each of the third and fourth baffles inclining in a direction away from the second baffle and toward the front wall.
 12. The furnace-cooling plate of claim 10, the streamlined protrusion projecting from the second baffle in a direction toward the third section of the first baffle, and each of the third and fourth baffles including a streamlined protrusion projecting in a direction toward the third section of the first baffle.
 13. The furnace-cooling plate of claim 12, each of the third and fourth baffles including a first end portion adjacent the second baffle and a second end portion remote from the second baffle, and the streamlined protrusions of the third and fourth baffles being located at the second end portions of the baffles.
 14. The furnace-cooling plate of claim 12, each of the third and fourth baffles including a side surface facing away from the third section of the first baffle, and the side surfaces of the third and fourth baffles being free of protrusions.
 15. The furnace-cooling plate of claim 12, the body including a top wall and a bottom wall, and each of the streamlined protrusions including a generally cylindrical surface extending from the bottom wall to the top wall.
 16. The furnace-cooling plate of claim 10, each of the third and fourth baffles being spaced from the second section of the first baffle a distance less than the distance of the inner end portion of the second baffle from the second section of the first baffle.
 17. The furnace-cooling plate of claim 10, the second baffle having a side surface facing away from the third section of the first baffle and extending to juncture of the second baffle with the backwall, and the side surface of the second baffle being free of protrusions.
 18. The furnace-cooling plate of claim 17, the body including a top wall and a bottom wall, and the streamlined protrusion projecting in a direction toward the third section of the first baffle and including a streamlined surface extending from the bottom wall to the top wall and joining the side surface of the second baffle.
 19. The furnace-cooling plate of claim 10, at least a terminal portion of the third section of the first baffle inclining away from the second sidewall in a direction toward the second baffle.
 20. The furnace-cooling plate of claim 10, including coolant supply means communicating with the first coolant passageway, and coolant discharge means communicating with the second coolant passageway.
 21. The furnace-cooling plate of claim 20, the second baffle including a vent aperture located adjacent the backwall.
 22. The furnace-cooling plate of claim 21, the body including a top wall, and the vent aperture being located adjacent the top wall. 